1. Field of the Invention
This invention relates to subsoil chisel plows which include a plurality of chisel blades, and more particularly, to chisel plows of the type described which are adapted for towing behind an agricultural tractor by means of a towing tongue connected to a single central towing point at the rear of the tractor.
2. Brief Description of the Prior Art
With the advent in the last 20 years of high-powered agricultural tractors, improvements in plows which facilitate plowing to a greater depth have been made, since such plows can generally be effectively pulled by tractors of relatively greater horsepower. One form of plow which has been used for the purpose of deep plowing has been a type which has been referred to as a chisel or subsoiler plow. Such plows usually include a plurality of transversely spaced chisel blades which are relatively thin arcuate blade members curving to a forwardly projecting point at the lower end thereof, and capable of chiselling or wedging deeply into the earth so as to break through the plow pan layer and penetrate to the moister earth frequently located below the hard plow pan layer present in some soils. One type of such subsoiler chisel plow which has been especially effective is that which is shown and described in U.S. Pat. No. 3,450,212.
Many of the subsoiler chisel plows heretofore proposed are constructed for attachment to three-point hitch type agricultural tractors through linkages which connect to the plow frame at three laterally spaced points. Control of these plows can be more easily obtained by reason of the hydraulic system of the tractor permitting elevation and more selective control through the three-point linkage. Often such plows have been provided with gauge wheels, which are ground-engaging wheels mounted on the blade-carrying framework of the plow, and adjustable in their vertical relationship to the blades so as to control the depth of the soil to which the blades will penetrate during use of the plow.